Thread trimmer for buttonhole-sewing machines



March 12, 1929. A. F. CARLSON THREAD TRIMMER FOR BUTTONHOLE SEWINGMACHINES Original Filed June 1, 1926 8 Sheets-Sheet 1 s n m r O A m e m,x v a m n w F II a p p m m wiwfiw m B a E m u.. 5i 3 A .0 QB H w March12, 1929. A. F. CARLSON 1,705,0

THREAD TRIMMER FOR BUTTONHOLE SEWING MACHINES Original Filed Juhe 1.1926 8 Sheets-Sheet 2 Fig.2. 68 69 3 E lnvenfor. Axel FtCurlson yMWkf Ans March 12, 1929. A. F. CARLSON THREAD TRIMMER FOR BUTTONHOLE SEWINGMACHINES Original Filed Junel, 1926 8 Sheets-Sheet 3 3 8 w r. 0 mm Wm W2 3 q New m Cl Jm M .w 6 mm 8 E I mm mm Ma Q WN 0 I r -2: mm mg 9 mm Nma mm. .m @N 3 Anys.

March 12, 1929.

A. F. CARLSON THREAD TRIMMER FOR BUTTONHOLE SEWING MACHINES OriginalFiled June 1926 8 heets-Sheet 4 InvenTor. Axel F Carlson byMMAW.

ATTys.

March 12, 1929. A. F. CARLSON THREAD TRIMMER FOR BUTTONHOLE SEWINGMACHINES Original Filed June 1, 1926 8 heets-sheet 5 lnvenTor.

Axel FTCorlson WM WkW ATTys.

March 12, 1929. A. F. CARL$ON 1,705,044

THREAD TRIMMER FOR BUTTONHOLE SEWING MACHINES Original Filed June 1,1926 8 Sheets-Sheet 6 Fig.6.

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lnvenTor.

Axel F Carlson kfw - ATTys.

March 12, 1929. c sofl 1,705,044 I THREAD TRIMMER FOR BUTTONHOLE SEWINGMACHINES Original Filed June 1, 1926 8 Sheets-Sheet 7 InvenTor. Axel F.Carlson bygemolwkfwaMj ATTyS.

March 12, 1929. A. F. CARLSON THREAD TRIMMER FOR BUTTONHOLE SEWINGMACHINES 8 heets-Sheet 8 Original Filed June 1, 1926 lnvenTor. Axel FCarlson yfaw Mam Patented Mar. 12, 1929.

UNITED STATES PATENT OFFICE.

AXEL F. CARLSON, OF CAMBRIDGE, MASSACHUSETTS, ASSIGNOR TO THE REECE BUT-TON HOLE MACHINE COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OFMAIN E.

THREAD TRIMMER FOR BUTTONHOLE'SEWING MACHINES.

Application filed June 1, 1926, Serial No. 112,810. Renewed June 8,1928.

This invent on relates to sewing machines and particuhirly to means fortrimming the thread at the end of the sewing operation. The invention isherein illustrated as embodied in a sewing machine of the type shown inmy co-pending application Serial No. 79.5233. filed January 6th. 1926.

in the device herein illustrated the tread trimmers are actuated at theend of each sewing operation by power mechanism which is normally idlebut which is set in operation by the action of the stopping mechanism inbringing the sewing inslrumentalities to rest. The trimming mechanism isof that known type which is constructed to trim the thread twice foreach sewing operation. once at the completion of the sewing operation inorder to cut the thread leading to the source of supply and again at thebeginning ot' the. next sewing operation.

Another feature of my invention relates to a novel trimmer adapted forthese two trimming operations. which trimmer is formed with twooppositely-disposed cutting edges, one of which is active in trimmingthe thread at the end of the scam and the other of which is active intrimming the thread at the beginning of the seam.

The device also includes a. novel pull-ofi' me hanism for pulling otl'both the upper end th" under thread at the end of the sewing operationand for holding each thread end during the time that the machine is atrest and until the next sewing operation is begun.

The invention further includes various novel features and constructions.all as will he more t'ull hereina'iter set forth.

in order to give an understanding of the invention l have illustrated inthe drawings a scicctevi embodiment thereof which will. now he dcscrihedafter which the novel featin-cs will be pointed out in the appendedclaims.

Fig. l is a. side view of a sewing machine havin the improveincntsapplied thereto;

Fig. Q. is a plan. view of the work-supporting arm and work clampsthereon together with the means for trimmingtlu upper thread and h ldingthe trimmed nd;

ig. 3 is a side view of Fig. 2;

Fig. T is a sectional view on substantially the line it 4?. Fig. l,iliustjating the poweracluating mechanism for operating the threadcutter;

Fig. 5 is a section on substantially the line 55, Fig. 4;

Fig. 6 is a fragmentary view illustrating the devices for controllingthe driving clutch;

Figs. 7 and 8 tragmentary views showing part of the power-actuatedmechanism for operating the upper thread holder;

Figs. 9 and 10 are fragmentary views showing the power-actnatcd meansfor operating the upper thread cutter;

Figs. 11 and 12 are fragmentary views illustrating the operation of theupper thread holder and cutter;

Fig. 13 is a fragm ntary view illustrating the mechanism for actuatingthe under thread trimmer and holder;

Fig. 14- is an enlarged fragmentary perspective view of the under threadpull-ofi' de vice;

Fig. 15 is a view illustrating the under thread cutter;

Fig. 16 is a view illustratim the under thread pull-off.

Fig. 17 is a section on the line 17-47, Fig. 3.

As stated above the present invent-ion is shown as emhodied in a sewingmachine which is similar to that illustrated in my copcnding applicationSerial No. 79 5323, filed January 6th, 1926. said. machine being a twothread buttonhole sewing machine. The sewing machine has the frame 1from which ex tends the usual overhanging arm 2 carrying the upperthread-manipulating mechanism and from which also extends a lowerhorizontal work-sup )orting arm 3 on which the work in is supported. Theupper thread-manipulating mechanism comprises the usual needie 4 whichis carried 1 a vertically-reciprocating needle bar 5. and the. underthreadmanipulating mechanism, which is not shown herein. ma v he in theform of the usual oscillatory hook which takes loops of needle threadand casts them about a shuttle in a well-knownv way.

The operating mechanism is driven from a driving shaft 6 which in turnis actuated from a constantly-rotating driving pulley 7, the latterbeing driven by the driving belt 8. This driving pulley 7 is connectedto and disconnected from the driving shaft 6 through the medium of a.suitable clutch, (not shown) situated in a recess in the pulley '7, saidclutch being controlled by a cone-shaped clutch actuator 9 which isslidably mounted on the shaft (5, movement of the clutch actuator towardthe left Figs. 4 and 6 throwing the clutch into engagement and movementto the right into the position shown in Figs. 4 and 6 releasing theclutch.

The clutch actuator 9 is controlled by a clutch-controlling rod 10 whichis slidably mounted in the frame. said rod having fest thereon a forkedarm ll, the fork of which engages in a groove 12 in theclutch-controlling member 9 so that movement of the rod 10 in thedirection of its length will throw the clutch into engagement or releasethe clutch. The clutch-actuating rod 10 is given its clutch-engagingmovement by means of an elbow lever 13 pivoted to the frame at 14, thevertical arm 15 of said elb v lever engaging the end of the rod 10.\Vhen the horizontal arm 13 is pulled downwardly the clutch-controllingrod 10 will be shifted to the left 4 and 6 thereby throwing the clutchinto engagement and setting the machine in opera tion.

A suitable latch device is provided for automatically engaging the rod10 when the clutch has been thrown into engagement, which latch devicelocks said rod in its operative position and maintains the clutch inengagement. This latch is automatically released at the end of thebuttonhole and when so released the rod 10 will be retracted into itsinoperative position by means of a suitable spring 16. The latch forlocking the rod 10 in its operative position is indicated at 17 and itis adapted to engage automatically in a notch 118 formed in the rod 10when the latter has been thrown into its operative position. The latchis released automaticallv by suitable mechanism. all as shown in myabove-mentioned a 'ipliration.

The elbow lever 13 may be operated in any suitable way. It herein shownas having a link 18 )ivoted to the horizontal arm. which link is a aptedto be actuated by a treadle or other startii'ig mechanism. The link isshown as extending through a head 19 fast on the end of a connection :20that leads to a tread le or other starting device. said link having acollar 21 thereon so that when the connection 20 is moved downwardly andthe head 19 is brought against the collar 2t the elbow lever 13 will beactuated to throw the clutch. Said elbow lever has a sprin connectedthereto which tends to return it to its initial position shown in Fig.4.

Associated with the starting mechanism above described is a stopmechanism by which the machine is brought to rest at the end of thestitching operation. This stop mechanism is similar to that shown in myabove-nientioned application Serial No. 79,523. and it comprises a stopmotion block 88 which is rigidly mounted on the clutch-controlling rod10 and which yieldingly carries a stop dog 89 that co-operates with astop cam 90 in bringing the machine to rest This stop cam 90 is fast onthe shaft 6. When the clutch-controlli11g rod 10 is shifted to the leftFigs. 4 and b to throw the clutch into engagement the stop motion block88 and stop dog 89 are -arried to one side of the path of movement ofthe stop cam 90.

When the latch 17 is released at the end of the stitching operation andthe clutch-controlling rod 10 is shifted to the right into the positionshown in Figs. 4 and 6 thereby releasing the driving clutch the stop dog89 will be carried into the path of movement of the stop cam 90 andduring the rotation of the shaft said stop cam will engage the stop dogthus bringing the driving sha ft (3 to rest.

The work 20 is held by a suitable work holder comprising under clamps 23and upper clamps 24. Both clamps are mounted on a work-supporting plate25 which in turn is supported on the arm 3 so that it can movelongitudinally of the arm and also transversely thereof. The movementlongitudinally of the arm is that which gives the work its feedingmovement during the stitching along the side of the buttonhole and themovement transversely of the arm is that which gives the work a joggingmovement for forming the barring stitches at the end of the buttonholeall as usual in buttonhole sewing machines of this type. The means forgiving the work holder its movement may be all as shown in myabove-mentioned co-pending application Serial No. 79.523. and as itforms no part of my present invention I have not deemed it necessary toillustrate it herein.

The upper work clamps 24 are carried by arms 26 which extend from theupper end of a rocking member 27 that is pivoted on a shaft 28 carriedby the clamp plate 25. These upper work clamps are yieldingly heldagainst the work by means of springs 29 and at the end of eachbuttonhole they are raised and held raised by means of a latch 30 whichengages a projection on an elbow lever 31 pivoted at 32, the horizontalarm 33 of said elbow lever engaging the under side of the arms 26 thusholding them raised.

When the machine is started the latch is automatically released thusallowing the clamps to close and this is accomplished by a lever 34pivoted to the bed at 35 and having a roll 36 adapted to engage a camface 3? on the under side of the latch. The lever 34 is connected by alink 38 with an elbow lever 39 which is pivotedto the frame and whichhas a link 40 connected thereto which extends through the head 19. saidlink 40 having a collar 41 thereon. The collar 41 is slightly above thecollar 21 and hence when the eonnection 20 is moved downwardly theinitial downward movement will act through the connections 40, 39, 38and 34 to raise the latch 30 and release the work clamps and continueddownward movement will then throw the clutch into engagement and startthe mechanism. The spring 42 acting on the lever 34 tends to return itto its normal position.

The work clamp and means for controlling it are or may be all as setforth in my copending application Serial No. 79.52;, or my (o-pendingapplication Serial No. 112.507 tiled May 29, 1926.

As stated above the present invention rclates to a novel means torcutting the needle thread at the end of the sewing operation and holdingthe severed end until after the next stitching operation has been begunand then cutting the held end directly after the second stitchingoperation has been begun, and also novel means for trimming the underthree d and holding the severed end, the thread trimmers and the threadholders being actuat by power mechanism which is normally in activeduring the stitching on the buttonhole but which is thrown intooperation by the stopping mechanism when the stitching on the buttonholehas been con'ipleted.

The upper thread trimmer is a blade 43 having the two oppositelydisposed cutting edges 44, 45. This cutting blade operates in atransverse slot formed in one of the work clamps and is carried by ashank 46 which in turn is secured to the end of an arm 47 that ispivoted at 48 to one of the upper work-clamping arms 26. Thecutter-carrying arm 47 is provided with a lateral extension 49 which isacted upon by a spring 50 that normally tends to hold the cutterrelative to the work clamps in the position shown in Figs. ll and 12, inwhich position it is at one side of the line of sewing. The trimming ofthe thread at the end of the seam is accomplished by a transversemovement of the blade into the position shown in Fig. 2 resulting from aswinging movement of the arm 47. as will presently be described.

Associated with the upper thread cutter is a thread holder which seizesthe. needle thread between the needle and the work and holds or gripssaid thread while it is being cut and also maintains a hold on thethread until the next sewing operation has begun as usual in devices ofthis type. This thread holder is indicated at 51 and it is in the formof a hook carried by a swinging arm also pivoted to the clamp-carryingarm 26 at 48. The arm 52 is acted on by a spring F3 which tends nor--mally to move said thread holder from the position shown in Fig. 2 tothat shown in Fig. 12.

This thread holder lies in contact with the upper surface of one of thework clamps and is adapted to grip the needle thread between itself andsaid work clamp.

During the stitching on the buttonhole the upper thread holder andcutter occupy the po sition shown in full lines Fig. 12. \V hen thestitch-forming mcchanisn'l has come to rest the thread holder is movedfrom the full line position shown in Fig. 12 back to the full lineposition Fig. ll during which movement the thread holder engages theneedle thread I, pulls otl a length thereotand clamps it against. theupper face of one of the work clamps. Alter this has been done thecutter is moved into the position shown in Fig. 2 across the line ofstitching and the edge 44 of the cutter will actto cut the needle threadt between the thread holder and the work, the severed end of the thrc: lleading to the needle being retained by the thread holder.

The thread holder 51 and thread cutter 43 are normally held by theirsprings 53 and 50 in the position shown in Fig. 12 and the operati vemovement of these parts into the position shown in Fig. which is themovement by which t upper thread is gripped and cut. is derived frompower.ictuated mechanism which is ormally idle during the sewing of thebuttonhole. but which is rendered operative by the action of the stopmotion in bringing the machine to rest. Such poweractoatcdliltilltt'lllslll comprises a cam 54 mounted on a stud $3.3 carried bythe frame. This cam is normally idle during the stitching on thebuttonhole but at the end of the stitching it is connected to aconstantly rotating member 56 through the medium of a onc revolutionclutch so that the cam will make one revolution and then come to rest.During this one revolution the cam actuatcs a mechanism iich moves thethread holder 51 and the thread cutter 4Z3 positively into the )siti n1shown in Fig. in which position thev are latched as will be presentlydescribed.

The c ntinually rotating member 56 is in the form of a gear memberloosely mounted on the stud 55 and meshing with a. g ar 57 rigid withthe driving pulley 7 so that the gear Fill will be rotating whenever thepulle is rotating.

The clutch by which lh the gear 56 similar to that shown in my copendingapplication to ial No. and also similar to that shown in the applicationof John Kicwic'z. Serial ffo. 115th. tiled December 15th. 1925. Thisclutch comprises a clutch pin 58 carried by the cam l and acted on by aspring 59 which tends normally to throw the clutch pin into clutchingengagemcnt with the coustautly-rotating member 56. Said clutch pin isnoru'ially held disengaged by means of a clutch dog (it). This clutchdog is in the town ot an arm carried by a rock shaft (31 and when theshaft is turned anti-clockwivc l ig. l the clutch dog will be raised outof or agcmcnt with the herd of the clutch pin on and the latter will tchthe cam to the constantly-rotatin55 member. said clutch pin beingretracted again by the clutch dog when the cam has e cam is clutched tomade one revolution as usual in one-revolution clutches.

its stated above this clutch is actuated by the stop motion. he shaft 61has fast thereon an arm (32 carrying an adjusting screw 63 which isadapted to be engaged by an arm (it fast to the stop motion block 88.When the stop motion operates to bring the shaft 6 to rest as abovedescribed the engagement of the cam so with the stop dog 89 will givethe stop motion bloc 88 a slight clockwise movement (see Fig. 5) thuscarrying the arm 64 into the dotted line position, in which position itwill engage the stop screw 63 and give the shaft 61 the requisiteturning movement to release the dog from the clutch pin, thus allowingthe clutch to become operative to clutch the cam 54 to theconstantly-rotating member 56. The movement of the arm 64 into thedotted line position is momentary only and, therefore. as soon as theclutch pin has been released the clutch dog will return to its normalposition shown in Fig. 1 ready to effect a disengagement of the clutchpin upon the completion of the rotation.

The cam 51 operates a lever 65 fast on a rock shaft (it; and said rockshaft. has fast thereon another arm 67 which is connected by a link (38to a slide 69 that is slidably mounted on the bed of the machine. Thecam 54 gives the slide (39 a positive movement to the left 3) and suchmovement gives rocking movement to a rocking actuating member 70 hit-hpivoted to the bed at 71. This member It) has a stud 72 extendingtherefrom on which is mounted a roll 73 and the slide 69 is providedwith an inclined or am face 74: t is adapted to engage the roll 73 whenthe le is moved to the left Fig. 3. The engagement of the cam face 74with the roll during such movement of the slide will rock the member 70toward the left Fig. 3 about its pivot 71. and such rocking movementwill first operate the thread holder 51 to cause it i the needle thread,as shown in Fig. 17, l than ca use the cutter to move into the po itioniown in Fig. 2 and dotted line po- .lil l 17. thereby cutting the threadbe- .en the thread holder and the work. The tin-mid h liter arm 52 isprovided with a lateral extension 75 which is connected by a link To toa rocking member 77 pivoted at 78 to the member 27 that carries theupper work clamps.

The power-ac uated member 70 carries a roll 79 which is a apted toengage the end face 80 of the rocking member 77 as shown in Fig. 7. Theengagement of the roll 79 with the face 89 is at a point below the pivot78 and hence as the member 70 swings toward the left Fig. 7 from thefull to the dotted line position the engagement of the roll 79 with theface 80 will swing the member 77 into the position shown in Fig. 8thereby drawing backwardly on the connection 76 and positive ly swingingthe thread holder into the position shown in Fig. 2 againstthe action ofthe spring 53. This movement of the member 77 and thread holder occursduring the initial forward swinging movei'nent of the member 70 d no tothe action of the slide 69. The member 77 is so constructed that afterthe swinging member 70 has reached the dotted line position Fig. 7 andhas thus actuated the thread holder the roll 79 will pass onto thesurface 179 which is at that time concentric with the pivotal axis 71 sothat during further movement of the member 70 the roll simply movesforwardly on the surface 179 and thus holds the member 77 in theposition shown in Fig. 8 while the thread cutter is given itsthreadcutting movement.

The lateral extension 49 of the thread-cutter carrying arm 47 isconnected by a link 83 to a swinging member 8-1 also pivoted on the pin78 (to-axially with the member 77. The stud 7 2 carried by thepower-actuated member 70 has secured thereon a pusher or thrust memberwhich is adapted to engage the swinging member 81- at a point below itspivotal point 78. as shown in Fig. 9, and hence the swinging movement ofthe power-actuated member 70 will operate to swing the member 8a intothe position shown in Fig. 10 and through the connection 83 give thecutter its thread-cutting movei'nent, that is, movement from the full todotted line position Fig. 17 or from a position shown in Fig. 11 to thatshown in Fig. 2.

The construction is such that as the member 70 swings forwardly the roll79 will act on the member 77 before the pusher 85 acts on the member 84.Hence during the initial swinging movement of the member 70 from thefull to the dotted line position Fig. 7 the roll 79 will act on themember 77. as shown in Figs. 7 and 8, thereby actuating the threadholder and during the further swii'iging movement of the member 70 thepusher 85 will operate the swinging member 84 and thus give the threadcutter its thread-cutting movement. During this further swingingmovement the roll 79 merely follows over the concentric face 179 andthus holds the member 77 in the position shown in Fig. 8.

\Vhen the member 70 has completed its forward movement and has swung themember 84 into the position shown in Fig. 10 both swinging members 77and 84 will be automatically latched by a latch 81 which is pivotallymounted on the pivotal rod 28 and is adapted to engage teeth orshoulders 82 and 86 formed on the members 77 and 84 respectively. Thislatch is counterweighted as shown at 87 so that it automatically clicksover teeth 82 and 86 the members 77 and 8 1 are operated.

With this construction. therefore. as the cam 54 makes its singlerotation at the end of the sewing operation the thread holder will firstbe given a positive movement by said cam from the position shown in Fig.12 to that shown in Fig. 2 thereby gripping the needle thread andsubsequently the cutter will be moved from the position shown in Fig. 12to that shown in Fig. :2 thereby to cut the needle thread between thethread holder and the work and after the thread holder and cutter havebeen moved into these positions they are automatically retained in suchpositions by the latch 81.

\Vhen the stitching on the next buttonhole is started the end of theneedle thread is still retained by the holder 51 and after the stitchinghas progressed to a certain point the thread cutter is released from thelatch 81 and is allowed to swing into the position shown in Fig. 11under the influence of its spring 50. During this movement the cuttingedge 45 engages the end of the needle thread which is retained in theholder and trims it close to the work. 'lhereafter the thread holder 51is released from the restraining influence of the latch 81 and isallowed to move into the position shown in Fig. 12 u nder the influenceof its spring 53. The cutter and thread holder are then set in positionready for the operation of seizing and holding the thread at the end ofthe buttonhole and then cutting the thread. This releasing movement ofthe latch is accom plished through the medium of a cam projection 88adjustably secured to the bed and with which the tail or end 8'? of thelatch engages during the feeding movement of the work. As the tail 87rides up the inclined cam face 88 it will turn the latch as will bereadily understood thus withdrawing it from the shoulders 86, 82.

In order that the cutter may be first released to cut the thread whileit is still held by the holder the point of the tooth 86 is situatedslightly above the point of the tooth 82 so that as the latch is swungdownwardly by the weighted tail 87 riding over the pro ection 88 saidlatch will be withdrawn from the shoulder or tooth 86 thus releasing thethread cutter before said latch is withdrawn from the shoulder or tooth82. This will give a proper sequence of operations in the release of thethread cutter and thread holder.

The machine herein shown is also provided with means for pulling off alength of under thread at the end of each sewing operation and thencutting the under thread close to and beneath the work. This underthread pull-off and cutter is also actuated from the rock shaft 66. Theunder thread pull-off is in the form of a resilient arm 91 (see Fig. 16)which is carried by a rocking member 92 pivoted at 93 to the under sideof the bed frame. This rocking member has a fork a; which embraces astud 95 carried by a slide 96 which operates beneath the bed frame. Therear end of the slide is provided with an opening 97 in which isreceived the lower end of a lever 98 that is pivoted to the frame at 99,

the upper end of said lever having a slot 100 therein in which isreceived a pin 101 carried by the lever arm 67. When, therefore, therock shaft 66 is turned by the cam 54 thereby to operate the upperthread cutter, the corresponding movement of the arm 67 will operatethrough the lever 98 to force the slide 96 rearwardly. Such rearwardmovement will saving the member 02 and the pull-01f arm 91 into thedotted line position Fig. 16 thus carrying the pull-oii' arm across thesewing opening 102 and engaging the under thread thereby pulling oil alength of the latter.

This pull-otf arm 01 is constructed so that it not only pulls oil alength of under thread but also grips and holds the under thread. Forthis purpose the wire forming the pulloff arm 91 is bent into a coil103. In forming the coil the wire is given a backward turn, as shown at10 1, Fig. 14, and then is bent into the coil formation. This forms atapering throat 105 which is so situated that when the pull-off armswings into the dotted line position Fig. 16 the under thread to will becaught in the tapering throat 105 and will be gripped slightlv betweenthe turns of the coil.

After the thread pull-011' arm 01 has thus operated to pull olf a lengthof thread and to grip the latter the under thread is cut by an underthread cutter 106. (see Fig. 15) which is also actuated by the slide 96.This cutter is pivotally mounted at 107 on the top of the work-supporting arm 3 and beneath the workholding plate 25, said plate beingremoved in Fig. 15 to better show the construction of the cutter. Thiscutter 106 has a cutting edge 108 at its end which operates directlybeneath the throat plate 109. Said cutter member 106 is connected at itsrear end to a block 110 which is slidably mounted in a slot 111 in thearm 3, said block having on its under side a pin 112 which is confinedbetween two arms 113 and 114 carried by the end of the slide 96. Thecutter member 106 also has a pin 115 depending therefrom and operatingin an inclined slot 116 formed in the bed.

With this construction the movement of the slide 110 toward the rearwill produce a forward swinging movement of the under thread cutter dueto the movementof the pin 115 in the slot 116, such forward movementcausing the cutting edge 108 to engage the under thread leading from thework through the throat plate 109 and thereby severing said thread closeto the work.

The arms 113 and 114 are spaced apart so as to allow some lost motionand the purpose of this is to provide the proper time relation betweenthe operation of the thread pull-off and the cutter, it being desirablethat the pulloff should operate first to pull off a length of threadafter which the cutter should operate to cut the thread. lVith the partsin the position shown in Figs. 15 and 16 it will be observed that duringthe first or initial movement of the slide 96 the pull-off arm 91 willbe swung toward the dotted line position Fig. 16 thereby pulling olf alength of thread and after the lost motion between the arm 11 i and thepin 112 has been taken up then dur ng further movement of the slide 96the block 1 it) will be actuated thereby operating the under threadtrimming knife.

The pin 95 is shown as acted on by a return spring 117 which restoresthe parts to their normal position as the arm 65 passes down onto thelow portion of the 1am I have also provided herein a safety device whichhas for its object to prevent the operation of the thread trimmers whilethe s'titchforming mechanisn'i in operation. In other words, this safetydevice positively holds the thread trimmers inoperative while thestitching is being performed and releases the thread trimmers foroperation only when the stitchforming mechanism has been brought torest.

It will be remembered that the trimmers set in operation by the actionof the stop motion in giving the arm (32 a momcn turning movement intothe dotted line position Fig. 5 thereby to release the clutch dog 60 andallow the clutch pin 58 to become operative to clutch the cam 54 to theconstantly-operating member 56. The safety device is in the form of alatch which is adapted to lock the arm (32 in the full line positionFig. This latch is shown at 120 and is pivoted to the train: at 121. Itis formed at its upper end with a nose 122 which is adapted to latchover the portion 123 of the arm (32, said portion having a lip 124 whichengages the nose 122 and thus locks the arm 62 from movement. Thislocking latch 120 is shown in its inoperative position in Fig. 4 and itis acted on by a spring 12.? which tends to swing it into its operativeposition in engagcn'ient with the lip 12%.

Means are provided whereby the locking latch 120 will be moved into itsinoperative position when the clutch-controlling rod is released and isshifted into a position to render the stop motion operative. The arm 64is provided with a lug 126 which engages a projection 127 on the lockinglatch when the stop motion block moves from the position it occupieswhen the driving pulley T is i'flutchcd to the shaft 6 into the stoppingposition shown in Figs. 4 and 6 and such engagement of the ear 126 withthe projection 127 swings the latch into the position shown in Fig. iand thus unlocks theleverarm 62. \Vhen the rod 10 is shifted to the leftFigs. 4 and 6 to start the machine by clutching the pulley 7 to thedriving shaft 6 such movement carries the car 126 away from the lug 127and the spring 125 then acts automatically to swing the locking latchinto its operative position, in which position it locks the arm 62 frommovement and thus prevents the possibility of the cam 54 being clutchedto the constantly-driving member 56. When, however, the stop motion isactuated to bring the serving mechanism to rest then the locking latch120 will be released so as to permit the operation of the threadtrimmers as above described.

The construction is such that when the clutch-controlling rod 10 isshifted to clutch the driving pulley 7 to the shaft 6 the locking latch120 will come into its operative position just before the stop dog 8%)is moved out of engagement with the. stop cam 90. ace the arm 62 will belocked just before the clutch is started in operation, the advantage ofwhich is that there is no possibility that the cutters can be actuatedaccidentally except at the proper time in the sequence of operations.

While I have illustrated herein a selected embodiment of the invention 1do not wish to be limited to the constructional features shown.

I claim:

1. Ina buttonhole sewing machine, the combination with stitch-forn'iinemechanism, of work-holding means, a thread holder, a thread cutterl'iaving two op iositely-disposed cutting edges, means to move thethread cutter in one direction to cut the thread at the end of the seamand in the other direction to cut the thread at the beginning of theseam.

2. In a sewing machine adapted to sew a short seam and then come torest. the combination with stitch-forming mechanism, of Work-holdingmeans, a thread holder, a thread cutter having two oppositely-disposcdcutting edges, power-actuated mechanism to more the cutter in onedirection, and a spring to move it in the other direction. movement inone direction operating to cut the thread at the end of the seam and inthe other direction at the beginning of the seam.

3. In a sewing machine adapted to sew a short seam and then come torest, the comhination with stitch-forming mechanisn'l, of work-holdingmeans, a thread holder. a thread cutter having two opposirely-disposedcutting edges, power-actuatml mechanism to move the cutter in onedirection at the end of the seam thereby to trim the thread between theholding means and the work, a spring to move said cutter in the oppositedirection at the beginning of the scam thereby to trim the held end ofthread.

4. In a machine adapted to sew a short seam and then come to rest. thecombination with a stitch forming meciianism. of workholding means, athread holder. :1 illifiihl cutter haying two oppositely-disposedcutting edges, power-actuated mechanism to operate the thread holder andthe cutter at the end of the seam to cause the thread holder to hold thethread and the thread cnttcr to cut the thread between the holding meansand the work. springs acting on said holder and cutter and opposing thepower-actuated movement thereof. a latch to hold said holder and cutterin the position given them by the power-actuated means, and meansoperated by the feeding" movement of the work-holding means to releasethe latch to permit the holder and cutter to return to their normalposition after he sewing operation has started.

5. In a huttonhole sewing machine. the combination with stitch-formingmerhmiism, of work-holding means. a driving and stop motion device fordriving the stit lntorming mechanism and blin ing it to rest, a threadholder, :1 thread cutter, power actuated mechanism controlled by thestop motion device when thestitch-formingmet-haniamisbrought to rest tocause the holder to hold the thread and the cutter to cut the threadbetween the holding means and the work. and s; 'ing' mechanism operatingto actuate the cutter to cut the held thread at the beginning of theseam.

6. In a sewing machine adapted to sew a short seam and then come torest. the combination with stitch-forming nw-hanism. of work-holdingmeans, a stop motion device for operating the stitch-forming me hanismand bringing it to rest at the end of the seam. power-actuated meanscontrolled by the stop motion device to pull ott 11 length ot needlethread, clamp the needle thread. cut the needle thread between thethread-clamping means and the work, pull oti' a length of under threadand cut. the under thread, and spring means o 'ierating to cut the upperthread at the beginning of the seam. v

7. In a sewing machine adapted to sew a short seam and then come torest. the combination with stitch-forming mechanism, of work-holdingmeans, a stop motion device for operating the stit h-torming mechanismand bringing it to rest at t he end of the seam, power-actuated meanscontrolled by the stop motion device to pull ott a length of needlethread, clamp the needle thread. cut the neodle thread between thethrea( i-clamping means and the work, pull otf a length of under threadand cut the under thread. spring means operating to cut the upper threadat the beginning of the seam, and means to lock the power-actuatedmechanism t'rom operation while the stitclnforming mechanism is inoperation.

8. In a huttonhole sewing machine, the combination with stitch-formingmechanisl'n, o't work-holding means, means to give the work-holdingmeans a feeding movement, a driving and stopping mechanism tor operatingthe stitcl1for1ning mechanism and bringing it to rest at the end of theseam, a thread cutter having two cutting edges, means operatingindependently of the stitchtorming mechanism but set in operation by thestop motion to move the thread cutter and cause one cutting edge thereofto trim the thread at the end of the buttonhole, and

means controlled by the feeding movement of the work-holding means togive the thread cutter a movement to cause the other cutting edge totrim the thread at the beginning of the seam.

9. In a buttonhole sewing machine, the combination with stitch-tramingmechanism, of wm-k-holding means, means to give the work-holding means afeeding nmvement, a driving and stopping mechanism for operating thestitch-forming nechanism and bringing it to rest at the end ot the "am,a

thread cutter having two cutting edges. a thread holder. means operatingindependently of the stitch-forming mechanism but set in operation bythe stop motion to cause the thread holder to grip the thread and thethreadcuttertocutthethrcad with one cutting edge at the end of thebuttonhole, and means controlled by the tecding movement of thework-holding means to cam-e the thread cutter to cut the thread with theother cutting edge after the seam has begun and to actuate the threadholder to release the trinnned end.

it). In a sewing machine, adapted to sew a short scam and then come torest. the combination with stitch-forming mechanism, ef work-holdingmeans, a thread cutter ha \ing' two oppositely-dis]iosed cutting edges.and means to move the thread cutter in one direction to cause onecutting edge to cut the thread at the end of the seam and in the otherdirection to cause the other cutting edge to cut the thread at thebeginning of the seam.

11. In a. sewing machine adapted to sew a short seam and then come torest, the combination with stitch-forming mechanism, of work-holdingmeans, a thread cutter having two oppositelydisposed cutt inc; edges,poweractuated mechanism to move the cutter in one direction to cause onecutting edge to cut the thread at the end of the seam, and a spring tomove the cutter in the opposite direction to cause the other cuttingedge to cut the thread at the beginning of the seam.

12. In a sewing machine adapted to sew a short seam and then come torest, the combination with stitch-forming mechanism, of work-holdingmeans, a thread cutter having two oppositely-disposed cutting edges,power-actuated mechanism to move the cutter in one direction, and aspring to move it in the other direction, movement in one directioncausing one cutting edge to cut the thread at the end of the scam and inthe other direction causing the other edge to cut the thread at thebeginning of the seam.

13. In a sewing machine adapted to sew a short seam and then come torest, the combination with stitch-forming mechanism, of work-holdingmeans, a thread cutter havmg two oppositely-disposed cutting edges,power-actuated mechanism to move the cutter in one direction at the endof the seam,

to cause one cutting edge to trim the thread, a latch to hold saidcutter in a position placed by the power-actuated mechanism, means torelease the latch at the beginning of the seam, and a spring to givesaid cutter a return movement thereby to cause the other cutting edge totrim the thread a second time.

14. In a buttonhole sewing machine, the combination with stitch-formingmechanism, of work-holding means, a thread holder, a thread cutterhaving two oppositely-dis; osed cutting edges, means operative at theend of the seam to give the thread holder a movement to cause it to gripthe thread and subsequently to operate the cutter to cause one edgethereof to cutthe thread, and means operativ a ter the next stitchinoperation has begun to move the cutter in the opposite direction tocause the other edge to cut the held end of thread and then to move thethread holder to reiease said thread {A ,iuent,

15. In a buttonhoie sewing machine, the combination with stitehformingmechanism, of work-holding means having a Feeding movement, a threadholder, a thread cutter having two oppositely-disposed edges, meansoperative at the end of the seam to cause th thread holder to grip thethread and suhsequently operate the cutter in one direction to cause onecutting edge thereof to cut the thread, and means operated by thefeeding moven'ient of the work holder after the next stitching operationhas begun to more the cutter in the opposite direction thereby to causethe other cutting edge to trim the thread and then to move the threadholder to release the thread fragment.

16. In a buttonhole sewing machine, the combination with stitch-formingmechanism, of work-holding means, a thread holder, a thread cutterhaving two opposit-elydisposed cutt ing edges, power-actuated mechanism0perative at the end of the seam to move the holder into a position togrip the thread and to move the cutter to cause one edge thereof to trimthe thread between the holder and the work, and means operative afterthe next seam has hegnn to move the cutter in the 0pposiie direction tocause the other edge to cut the held thread and then to move the threadholder to relez re the thread fragment.

ti. In a buttonhote sewing machine, the combination \Vi'i hstitchforming mechanism, of work-holding means having a feedingmovement, a thread holder, a thread cutter having; twooppositely-disposed cutting edges, power-actuated mechanism operative atthe end of the seam to move the holder into a position to grip thethread and to move the etltiOi' to rause one edge thereof to trim thethread between the holder and the Work, and means operated by thefeeding movement of the work holder after the next stitching operationhas begun to move the cutter in the opposite direction to cut the heldend of iili't ad and then to move the thread holder to rehz-zse, thethread fragment.

in testimony whereof, I have signed my name to this specification.

AXEL F. CARLSON.

